The wave gear device was invented by C. W. Musser (Patent Document 1), and since that time, a variety of inventions concerning wave gear devices have been made by many researchers, including Musser and the present inventor. A variety of inventions relating to the tooth profiles of wave gear devices have also been proposed. For example, the present inventor has proposed making the basic tooth profile an involute tooth profile (Patent Document 2), and has also proposed a tooth profile design method for deriving the addendum tooth profile of two gears in contact over a wide area by using a technique in which tooth meshing of the rigid internally toothed gear and the flexible externally toothed gear is approximated by a rack (Patent Documents 3, 4). The present inventor has also proposed an invention aimed at avoiding tooth profile interference caused by rack approximation (Patent Document 5).
The present inventor has further proposed a tooth profile provided with a large tooth depth and a wide meshing region in order to prevent ratcheting at the time of a high load torque in a wave gear device having a high reduction ratio and including over 160 teeth in the two gears (Patent Document 6).    [Patent Document 1] U.S. Pat. No. 2,906,143    [Patent Document 2] JP-B 45-41171    [Patent Document 3] JP-A 63-115943    [Patent Document 4] JP-A 64-79448    [Patent Document 5] JP-A 7-167228    [Patent Document 6] WO2005/043006 pamphlet